(Vertical distribution of biotic pollination systems in cerrado sensu stricto in the Triangulo Mineiro, MG, Brazil). Several factors can influence the distribution of floral resources and pollination systems in ecosystems, such as climate, altitude, geographic region, fragmentation of natural areas and differences in floristic composition along the vertical stratification. This study aimed to evaluate the distribution of the vertical stratification of biotic pollination systems in cerrado (sensu stricto) fragments in the Triangulo Mineiro. There was no significant difference (chi(2)(0.05,9)=14.17; P = 0.12) in total plant species richness among fragments, nor in the species richness of each layer (trees, shrubs, herbs and lianas) and the shrub layer was the best represented. Likewise, there was no significant difference between fragments for the systems of pollination (chi(2)(0 05,21) =13.80; P = 0.8778). Pollination by bees was the most common, corresponding to 85% of species in each fragment. In relative terms, plants pollinated by bees were dominant in all strata, reaching 100% for the lianas in fragments 1, 3 and 4 and for the herbs in fragments 1 and 4. In this study, based on floristic composition and distribution of biotic pollination systems in the vertical stratification...

Castor bean (Ricinus communis L.) is cultivated mainly for biodiesel production because of its oil-rich seeds; it is assumed to be an anemophylous species. But pollination deficit can lead to low productivity often attributed to other reasons. In this paper, we investigated pollination requirements, pollination mechanism, occurrence of pollination deficit, and the role of biotic pollinators in a large commercial plantation of castor bean. Our results show that R. communis bears a mixed breeding system favoring selfing by geitonogamy, although the wind promotes mostly outcrossing. We also found that the honey bee (Apis mellifera L.) foraging on castor bean can both transfer pollen from male to female flowers within the same raceme and boost the release of airborne pollen by male flowers. Both situations increase geitonogamy rates, raising significantly fruit set and seed yield. This is the first report of an animal foraging activity increasing seed yield in an anemophilous and geitonogamous crop and elucidates the role of biotic pollinators in castor bean reproduction.

The pollination biology and breeding system of Couepia uiti was studied. In this species, flowers opened at 06:00 AM anthesis, and nectar production began at around 0800 h, reached a maximum volume from 09:30 AM to 10:30 AM, and decreased thereafter. The nectar sugar concentration increased continuously, but showed an abrupt increase from 10:00 AM to 12:00 AM. Pollen release occurred at about 09:30 AM and was quickly collected. The stigmas became receptive at around 12:00 AM. The pollinators of C. uiti included the bees Apis mellifera, Xylocopa sp. and Bombus sp., and three species of wasps. This conclusion was based on the observation that these hymenopterans had C. uiti pollen on their bodies, visited the receptive flowers, and touched the anthers and stigmas, thereby promoting pollination. Of these floral visitors, A. mellifera was considered to be the most efficient pollinator. However, mixed pollination also occurred. The number of C. uiti flowers visited in the morning (n = 52) was three times smaller than in the afternoon (n = 62), and the species richness of floral visitors was also bigger in the afternoon (eight in the afternoon versus five in the morning). This finding indicated that these floral visitors preferred to exploit nectar rather than pollen. Controlled pollination experiments showed that C. uiti was a self-incompatible species that produced fruits only by cross-pollination. Treatments such as agamospermy and spontaneous and self-pollinations did not produce fruits.

This study aimed to investigate the floral biology and pollination requirements of sesame (Sesamum indicum L.), cultivar CNPA G2. The study was carried out at Barbalha, State of Ceará, and consisted of two phases: floral biology and pollination requirements. Flowers were observed as for time of anthesis, lifespan and stigma receptivity, and were applied the following pollination treatments: open pollination, hand cross-pollination, hand self-pollination, pollination restricted with tulle bags and pollination restricted with paper bags. Significant differences (p < 0.05) were detected between treatments for the number of fruits harvested 30 days after pollination. It was shown that the sesame plant presents a mixed-pollination system, because it can produce fruit whatever the type of pollination tested. Flowers are able to autopollinate and do not depend on external agents. Pollinations restricted with paper and tulle bags produced fruit with greater number of heavier seeds. It is concluded that sesame crop is able to autopollinate and benefit from both self-pollination and cross-pollination.

The objective of this study was to determine the influence of the number of visits by the honey bee (Apis mellifera L.) on the pollination rate of strawberry (Fragarla × ananassa, Duch.) flowers. Pollination rate is defined as the number of fertilized achenes divided by the total number of achenes per berry. ‘Veestar’ cultivar plants were caged before flowering began and cages were opened to observe bee visits. The cumulative effect of the number and length of visits to these flower significantly increased the pollination rate. Four visits with a total of approximately 40 s of foraging were required for adequate pollination. In the absence of pollinators, primary flowers had lower pollination rates than secondary and tertiary flowers. Pollen transported by bees is thus particularly important for optimal development of these first berries harvested for market.

Pollination is presented as a determining factor in the production of fruits in various fruit species, especially those that do not reproduce by parthenocarpy. This study aimed to evaluate the influence of self-pollination and cross-pollination of jelly palm in production and fruit quality. To this end, we used 14 genotypes of jelly palm of BAG of FAEM-UFPel, RS, Brazil. The treatments were: non-bagging (T1) and bagging with TNT (T2). Evaluated: average production cycle (days), average fruit weight (g), the average mass of pulp (g), pulp yield (%), average mass of pyrenes (g), number of fruits, equatorial diameter of fruits (EDF), longitudinal diameter of fruits (LDF), equatorial diameter of pyrenes (EDP), longitudinal diameter of pyrenes (LDP), relationship LDF/EDF, relationship LDP/EDP, amount of juice (ml), average number of almonds/pyrene (NA/P), almonds brocade/pyrene (%AB/P), average mass unitarian of almonds (AMUA), without almonds pyrenes (%WAP), skin colorimetry (??Hue), soluble solids (??Brix), titratable acidity (TA) ratio (SS/TA), juice pH, ascorbic acid (mg.100ml-1 juice), average date of flowering (DF) and average date of harvest (H). Self-pollination of jelly palm caused a reduction of the overall rates in the variables average mass of fruit...

Most plants require interactions with animals to facilitate pollination and successful sexual reproduction. However, the role of pollination in the formation and maintenance of geographical range limits is largely unexplored. I tested the hypothesis that pollination service declines with increasing elevation using Rhinanthus minor, a self-compatible annual pollinated by bumble bees (Bombus spp.), along two altitudinal transects in the Rocky Mountains of Alberta. Contrary to predictions, Bombus abundance estimated by pan-trapping and direct observations increased toward the upper range limit of R. minor and visitation rate to R. minor did not vary with elevation. Pollen deposition on stigmas declined with increasing elevation, though almost all flowers received more than enough pollen to fertilize all ovules. Accordingly, the seed set of pollen-supplemented flowers was not higher than that of open-pollinated flowers. The seed set of flowers isolated from pollinators was uniformly high, suggesting that autonomous self-pollination may buffer seed production from any altitudinal variation in outcross pollination. Given that pollinators were abundant and foraging on R. minor at high altitudes, it is unlikely that the upper range limit of R. minor can be attributed to a decline in Bombus-mediated pollination.; NSERC...

Controlled self- and cross-pollinations were conducted on flowers of five mature Eucalyptus nitens trees. Levels of self-sterility of the trees ranged from 25.8 to 93.6%. Pollen tube numbers in styles and ovule penetration by pollen tubes was investigated 2 weeks after pollination by fluorescence microscopy. There were no significant differences between treatments in the number of pollen tubes present in styles or in the percentage of ovules penetrated by pollen tubes. Embryology of material harvested 2 and 4 weeks after pollination was investigated by bright-field microscopy. Fertilisation had taken place by 2 weeks after pollination with nearly every ovule showing evidence of fertilisation. Cross-pollination resulted in a greater proportion of healthy, developing ovules, at both 2 and 4 weeks after pollination, compared with self-pollination. The proportion of degenerating ovules increased from 2 to 4 weeks after pollination. The reduced ability of E. nitens to set self-pollinated seed compared with cross-pollinated seed appears to be controlled by a post-zygotic mechanism. Differences in ovule size may potentially assist in the identification of trees incapable of setting self-pollinated seed.; Leanne M. Pound, Meredith A. B. Wallwork...

Amegilla spp. (Hymenoptera: Anthophoridae) have been suggested as potential native Australian alternative to overseas used bumblebees (Bombus spp.) for pollination of tomato in greenhouses. In this study, we investigate the effectiveness of Amegilla chlorocyanea Cockerell as a greenhouse pollinator of tomato, Lycopersicon esculentum Mill. We show that (1) a single buzz by a female increases tomato weight by 11% compared with pollination by using an industrial pollination wand, (2) multiple buzzes increase tomato weight compared with a single buzz, and (3) unlimited flower visits lead to an increase in fruit weight of 21% compared with wand pollination. These results are comparable with those achieved by bumblebee pollination and demonstrate that A. chlorocyanea is a valid alternative to bumblebees for greenhouse tomato pollination in Australia.

Tomato flowers (Solanum lycopersicum L.) in greenhouses require assisted pollination. Compared with pollination using a vibration wand, pollination by buzz pollinating bees results in improved seed set and consequently, higher fruit weight. We investigated whether there are further chemical and sensory differences between bee- and wand-pollinated cherry tomatoes, Solanum lycopersicum variety Conchita. The pollination method did not result in significant differences in concentration of soluble solids and titratable acidity. However, the concentration of soluble solids was significantly positively correlated with seed number. We suggest that an increase in the amount of soluble solids in the locular area, due to increased seed numbers, is counteracted by the effects of seed numbers on the growth of the walls, which occurs through cell elongation. In the sensory part of this study, a large, untrained panel significantly preferred bee-pollinated over wand-pollinated tomatoes and classified bee-pollinated tomatoes as having more depth of flavor than wand-pollinated tomatoes. Thus, bee-pollinated tomatoes taste better than wand-pollinated tomatoes, and it is likely that the sensory differences between the two groups of tomatoes are mediated through effects of pollination treatment on seed numbers. Future chemical and sensory studies of fresh tomatoes should take into account the effects of seed numbers and their possible effect on the distribution of chemical compounds within tomatoes.; Katja Hogendoorn...

journal article; We report a new obligate pollination mu-
tualism involving the senita cactus, Lophocereus schottii
(Cactaceae, Pachyceereae), and the senita moth, Upiga
virescens (Pyralidae, Glaphyriinae) in the Sonoran De-
sert and discuss the evolution of specialized pollination
mutualisms. L. schottii is a night-blooming, self-incom-
patible columnar cactus. Beginning at sunset, its ¯owers
are visited by U. virescens females, which collect pollen
on specialized abdominal scales, actively deposit pollen
on ¯ower stigmas, and oviposit a single egg on a ¯ower
petal. Larvae spend 6 days eating ovules before exiting
the fruit and pupating in a cactus branch. Hand-polli-
nation and pollinator exclusion experiments at our study
site near Bahia Kino, Sonora, Mexico, revealed that
fruit set in L. schottii is likely to be resource limited.
About 50% of hand-outcrossed and open-pollinated
senita ¯owers abort by day 6 after ¯ower opening.
Results of exclusion experiments indicated that senita
moths accounted for 75% of open-pollinated fruit set in
1995 with two species of halictid bees accounting for the
remaining fruit set. In 1996, ¯owers usually closed be-
fore sunrise, and senita moths accounted for at least
90% of open-pollinated fruit set. The net outcome of the
senita/senita moth interaction is mutualistic...

journal article; We studied variation in flowering phenology, fruit and seed set, and the abundance of the pollinators
of four species of night-blooming Sonoran Desert columnar cacti for up to eight years at one site in
Mexico and one year at one site in Arizona. We determined how spatiotemporal variation in plant–pollinator
interactions affects the evolution of generalized pollination systems. We conducted pollinator exclusion and
hand pollination experiments to document annual variability in pollinator reliability and to determine whether
pollination systems were redundant (different species are partially or totally substitutable) or complementary
(different species have an additive effect on fruit set). The cacti we studied included three species with generalized
pollination systems involving bats, birds, and bees (cardon, Pachycereus pringlei; saguaro, Carnegiea gigantea;
and organ pipe, Stenocereus thurberi) and one specialized moth-pollinated species (senita, Lophocereus schottii).
We predicted that the migratory lesser long-nosed bat, Leptonycteris curasoae, is a less reliable pollinator than
birds and bees, and that cacti with generalized pollination systems have more variable flowering phenologies
than the specialized species.
Annual time of peak flowering and mean size of flower crops were relatively invariant in saguaro and organ
pipe. Time of peak flowering in cardon varied by as much as six weeks...

Flowering plants display remarkable phenotypic diversity, especially in reproductive structures, much of which is thought to be associated with pollination by animals. Pollination syndromes are collections of floral traits (e.g. flower colour, shape, odour) that are associated with a plant attracting particular functional groups of animal pollinators. We explored the extent to which traits associated with the moth pollination syndrome translated into pollination by moths in the Pacific coast dune endemic Abronia umbellata and found mixed results: in one year of study, there was no difference in seed set by day- vs. night-pollinated inflorescences, but in another year of study, night-pollinated inflorescences set significantly more seed than those pollinated during the day. We integrate this work with tests of pollen and resource limitation of seed production and with seed set surveys of natural populations to address proximate and ultimate causes of low seed set, finding low rates of pollinator visitation, high pollen limitation of seed production in all populations studied, and no evidence of endogenous resource limitation of seed production. We propose that “excess” flowers may be functionally male, serving to increase outcross siring success.
The transition from self-incompatibility and obligate outcrossing to self-compatibility and predominant selfing is the most common evolutionary transition among the flowering plants and traits associated with outcrossing may become reduced across such shifts...

4 pages, 3 tables.; Due to the several advantages expected from growing self-compatible almond cultivars, breeding programmes have recently introduced self-compatibility as an important trait. However, doubts have arisen regarding the capability of the newly obtained self-compatible almonds to produce good yields in monovarietal plantations, and the commercial quality of the fruits from self-pollination. For this reason, in the last years several studies have been conducted to evaluate fruit set and fruit traits following self- and cross-pollination of self-compatible almonds. Their results showed inconsistencies for fruit set and for some of the fruit traits studied. Thus, while some studies showed no differences between both pollination types for any of the fruit traits, others clearly showed important differences with the detriment of self-pollination for commercially important fruit traits. The fact that some of these studies evaluated a low number of individuals and/or fruit traits, implies the need of a more complete study. In this work, 10 fruit traits were studied in 26 self-compatible almonds following self-pollination by bagging and open pollination treatments. In general, and despite a few individuals showed differences between both pollination types for two of the traits...

Insect pollinators, both managed and wild, have become a focus of global scientific, political and media attention because of their apparent decline and the perceived impact of this decline on crop production. Crop pollination by insects is an essential ecosystem service that increases the yield and quality of approximately 35% of crops worldwide. Pollinator declines are a consequence of multiple environmental pressures, e.g. habitat transformation and fragmentation, loss of floral resources, pesticides, pests and diseases, and climate change. Similar environmental pressures are faced in South Africa where there is a high demand for pollination services. In this paper, we synthesise data on the importance of different pollinators as a basis for services to South African crops and on the status of managed honeybees. We also focus on insect pollination services for the Western Cape deciduous fruit industry, which is worth ZAR9800 million per year and is heavily reliant on pollination services from managed honeybees. We discuss landscape and regional level floral resources needed to maintain sufficient numbers of managed honeybee colonies. In summary, the available literature shows a lack of data on diversity and abundance of crop pollinators...